In general, to hang or fix some articles on a tile wall or a glass surface making it difficult to use screws or nails, vacuum fixers using the principle such as a sucker formed on legs of an octopus are widely used. Such vacuum fixer has a suction plate formed like an upside-down dish. After the suction plate is put on a smooth surface such as glass or tiles and the inside air of the suction plate is removed, when the inside volume of the suction plate is forcedly widened, the outside pressure of the suction plate, namely, atmospheric pressure, is much higher than the inside pressure of the suction plate, and thereby, the vacuum fixer can be adhered on the adhered surface since the atmospheric pressure presses the suction plate.
Japanese Utility Model Laid-Open Publication No. So61-109367, which was published on Jul. 11, 1986, discloses a vacuum fixer. In the prior art, a wide pressing plate is formed by expanding the edge of a compression fixer, which is in the form of an upside-down dish and made of rigid material, and the pressing plate is put on a suction plate nude of soft material. At this time, a diameter of the pressing plate is a little larger than that of the suction plate, and the outer circumference of the pressing plate protrudes downwardly so as to cover the suction plate. The compression fixer has a screw shaft formed on the top portion thereof to lift up the suction plate, and the screw shaft has a grip for hanging an article.
However, the conventional vacuum fixer is considerably deteriorated in adsorptive force since the suction plate is hardened when the vacuum fixer is used for a long time period. Particularly, in the case where fine cracks or indented portions are formed on the adhered surface, since the suction plate does not form a perfect vacuum wall, it may never stick to the adhered surface.
To address the above problem of the prior art, Japanese Utility Model Registration No. 3014841, which was granted on Jun. 7, 1995, discloses a vacuum fixer, which has a screw shaft mounted on the upper portion of the center of a suction plate, a dome-shaped pressing plate for inserting the screw shaft therein and covering the upper surface of the suction plate, and a grip connected to the screw shaft protruding to the upper portion of the pressing plate. Expandably adhesive material, for instance, adhesive silicon, is fused on the edge of an adsorptive surface of the suction plate using an adhesive agent.
The expandably adhesive material used for increasing bonding force of the suction plate is a good attempt. However, because the suction plate is basically made of soft material, when the center of the suction plate is lifted up toward the pressing plate to widen the inside volume of the suction plate, the form of the edge of the suction plate may be distorted or a little sliding may occur between the adsorptive surface and the adhered surface, and particularly, the prior art cannot provide a perfect bonding force if there are indented portions on the adhered surface.
Meanwhile, Korean Utility Model Registration No. 302081, which was devised by the devisor of the present device, discloses a vacuum fixer in which a vacuum wall made of gel-type polyurethane is formed on an auxiliary air compressor (called a ‘pressing plate’ in the present device). When the auxiliary air compressor makes the inside of a suction plate vacuum, indented portions formed on the adhered surface are filled with the gel-type vacuum wall, so that the inside of the suction plate can be kept in a perfect vacuum condition. However, the above device still has several problems in that a structure between the vacuum wall and the suction plate leave somewhat to be desired, and in that the polyurethane material used for the vacuum wall is not specified.